Fun. Lost of symlinks. Can I use these to identify the drives to be
used in RAID pairs or for LLVM?

Yes

Well, that worked. And /etc/fstab is happy with
/dev/disk/by-id/ata-ST3750640AS-5QD4Z81L-part1 /bottom ext3 defaults,auto,rw,nodev 0 0
but /boot/menu/grub is not happy with
title Debian GNU/Linux, kernel 2.6.18-6-amd64 (new)
root /dev/disk/by-id/ata-ST3750640AS-5QD4Z81L-part1

Evidently, grub wants a different notation. The manual grup manual
provides hd and fd notation, but the drives are sd, and, again, how would

grub know which is which?

Grub2 or Grub legacy?
I have that trouble with USB disks, because Legacy wants
root (x,y)
hardcoded, none of that "by-id" stuff.
So I switched to http://stmaarten.globat.com/~supergrubdisk.org/index.php
"super grub disk" that allows me to state in menu.lst:
title 2.6.26-1-686 di install
findf /wd80_0jd-60.03
root $(out_device)

Key is that "findf", that looks for a file on any disk named
"/wd80_0jd-60.03" and uses *that* disk as root.
So in your case you would stick a file named
/ata-ST3750640AS-5QD4Z81L-part1 on the disk labeled by that and SGD
would stick the appropriate (x,y) in "out_device" and away you'd go.